The field of the disclosure relates generally to fault testing of real-time computer networks, and more specifically, to methods and apparatus for adding latency and jitter to selected network packets.
When fault testing real-time computer networks, for example, an avionics network to be deployed within an aircraft, insertion of faults at an individual packet address level into such networks is difficult. Certain network testing includes insertion of extra latency and timing jitter into a computer network to test the sensitivity of the devices on the network. More specifically, it is desirable to determine the impact on network operations when worst-case network conditions are encountered. In the aircraft context, computer network testing is utilized to test the sensitivity of avionics equipment to worst-case network conditions that might be encountered during a various phases of a flight.
However, and as mentioned above, insertion of faults into a network is difficult as preferred testing methodologies dictate that network faults such as timing delay and jitter, should be inserted in real-time, and only to certain selected network packets. Since a network may transport many different classes of traffic, this fault insertion should also occur without disturbing all other network traffic. In one relevant example, 99% of the network traffic must be passed without disturbance through the network, with faults inserted to only a small percentage of the network traffic. Such network testing naturally requires precise timing of software functions related to insertion and removal of faults.